The present invention relates to a support for the reed of a seam-weaving machine for joining the two ends of a plastics fabric by means of a woven seam. The reed has reed dents for shifting auxiliary weft threads against the fell of the fabric, the reed dents being pivotally mounted and, starting from the fabric end at which the auxiliary weft thread to be shifted in each case protrudes as a warp fringe, pressing successively against the auxiliary warp thread to be shifted.
Industrial plastic fabrics for uses in which an absolutely regular surface structure of the fabric is required, especially in the case of flat-woven plastic paper-forming fabrics, are made continuous by a woven seam. To produce a woven seam, warp threads are exposed to a length of e.g. 15 cm at the fabric ends which are to be joined to each other, the weft threads in this zone being removed. The so-called woven seam, in which the original weave binding is exactly reproduced, is formed from these warp thread fringes and the weft threads removed from the fabric. An auxiliary weaving shed or seam-weaving shed is spread out from the removed weft threads, the removed weft threads functioning as auxiliary warp threads. The warp thread fringes are inserted into this auxiliary weaving shed as auxiliary weft threads alternately from the two fabric ends. The warp thread fringes, i.e. the auxiliary weft threads, and the removed weft threads, i.e. the auxiliary warp threads, are as a rule monofilaments with a diameter of 0.1 to 0.5 mm and the woven seam is manufactured after the thermosetting of the fabric, so that the threads already have the corrugation or knuckle corresponding to the weave binding in question. To obtain a woven seam which has a high tensile strength and does not differ from the rest of the fabric in the patterning of the surface which is decisive for the marking in the paper, the auxiliary warp threads and the auxiliary weft threads must interweave with their knuckles in the fabric, so that a form-locking results. The interweaving of the auxiliary warp threads and auxiliary weft threads according to their knuckle is achieved inter alia because the reed does not shift the auxiliary weft threads simultaneously along the whole length, but the auxiliary weft threads are progressively shifted through the seam-weaving shed, starting from their point of emergence from the fabric end.
A reed which permits such a gradual shifting of the auxiliary weft threads is described in DE-U-81 22 448. The reed is movable into an operating position brought close to the fell. The reed dents pivotally mount on a shaft are kept back away from the fell by a rubber strip. Starting from the fabric end, they are pressed one after another against the auxiliary weft thread by a deflection member, against the elasticity of the rubber strip. The deflection member is a roller displaceable on a guide track and the roller is pushed along the reed dents over the whole seam width for every shifting process.
The same object is achieved according to EP-A-0 043 441 by a rotatably needle roller which has a plurality of flexibly elastic needles which are arranged in helical rows of needles. Also described as a further possibility in this publication is the shifting of the auxiliary weft threads by means of Z-shaped needles which are arranged in a guide bed alongside each other and individually axially displaceable. The needles engage in the shed with their front Z-end. The Z-shaped needles are pushed one after another against the fell by means of a coulisse so that the auxiliary weft thread is progressively shifted in a wave motion, starting from its point of emergence from the fabric end.